Continuous positive airway pressure (CPAP) machines are commonly used in the treatment of obstructive sleep apnea. These machines deliver a continuous stream of air to a patient's airway, producing a positive pressure that keeps the patient's airway open and allows for unobstructed breathing. Although CPAP machines provide an effective treatment for sleep apnea, they generally require electricity to operate. As such, the long term use of these machines may be costly for patients. They may also be inoperable in situations where electricity is unavailable, such as during power outages and in remote locations.
Nasal expiratory positive airway pressure (EPAP) devices, such as Provent™ and Theravent™, provide positive airway pressure during expiration, without requiring electricity. These small, disposable devices are temporarily affixed to a user's nostrils, and incorporate vents that are designed to open while the user inhales, and to partially close while the user exhales. The increased resistance during expiration produces positive airway pressure, which may be effective in treating conditions such as sleep apnea and snoring.
These EPAP devices do not, however, provide positive airway pressure during inspiration. Nor do they allow for control of respiratory parameters such as pressure, flow and tidal volume. Furthermore, some nasal EPAP devices may produce significant airway resistance during expiration and inspiration, which increases the work of breathing and may lead to Upper Airway Resistance Syndrome (UARS). Additionally, the devices may potentially become clogged with nasal secretions, rendering them useless or even dangerous in some circumstances.